Home-brew battery measuring station

[BrianG]

He is relying on the fact that the resistance in the metal will change as it gets longer. That, and the shunt resistor he is using to measure the current are the only things limiting the current. And I would hate to feel how hot that bar and resistor are getting! 300A @ 1.9v (in first vid) is 570w, even with one LiFe cell, and that heat has to be dissipated somewhere along that relatively low surface area. Even if you wanted to do this, it would be limited to a single cell and heat would become a problem after even aseveral seconds.